scholarly journals The structural stability of protein antigens adsorbed by aluminium hydroxide in comparison to the antigens in solutions

2007 ◽  
Vol 21 (5-6) ◽  
pp. 257-268 ◽  
Author(s):  
Yiwu Zheng ◽  
Xuxin Lai ◽  
Henrik Ipsen ◽  
Jørgen Nedergaard Larsen ◽  
Henning Løwenstein ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Structural Stability ◽  
Aluminium Hydroxide ◽  
Storage Temperature ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Protein Antigens ◽  
Adsorbed Protein ◽  
Vaccine Immunogenicity ◽  
Atr Spectroscopy

It is believed that antigens should be adsorbed onto adjuvants in vaccines. The adsorption-modified structure of antigens is important to understand the mechanism of adjuvants and vaccine immunogenicity. The structural stability of antigens is of major importance. The changes in structure can be induced by degradation and/or increase of storage temperature. In this study the structural stability of two model antigens, bovine serum albumin (BSA) andβ-lactoglobulin (BLG) were compared when they were adsorbed onto aluminium hydroxide and when they were in solutions using Fourier transform infrared – attenuated total reflection (FTIR-ATR) spectroscopy. The structural stability of these two proteins was studied at different temperature and during storages. The present results showed that the structure of antigens can be stabilized by adsorption onto aluminium hydroxide. Non-adsorbed protein antigens present in vaccines may facilitate the degradation of the vaccine.

Discrimination of Soil-Borne Fungi Using Fourier Transform Infrared Attenuated Total Reflection Spectroscopy

2008 ◽  
Vol 62 (3) ◽  
pp. 302-305 ◽  
Author(s):  
Raphael Linker ◽  
Leah Tsror(LAHKIM)
Keyword(s):  
Fourier Transform ◽  
Success Rate ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Economic Damage ◽  
Genus Level ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Soil Borne Fungi

Fourier transform infrared (FT-IR) attenuated total reflection (ATR) spectroscopy was used to discriminate five commonly encountered soil-borne fungi that cause severe economic damage to agriculture: Colletotrichum, Fusarium, Pythium, Rhizoctonia, and Verticillium. Contrary to previous studies related to microorganism discrimination using FT-IR-ATR spectroscopy, the pathogen samples were not dried on the ATR crystal, which is a time-consuming operation. Rather, after removing some pathogen filaments from the solution using tweezers, these were placed directly on a flat ATR crystal and pressure was applied using a pressure clamp. Following water subtraction, baseline correction, and normalization of the spectra, principal component analysis was used as a data-reduction step and canonical variate analysis was used for discrimination. Discrimination was performed at the genus level and at the strain level for Colletotrichum. For discrimination between the five fungi at the genus level, the success rate for the validation samples ranged from 75% to 89%. For discrimination between the two Colletotrichum strains, the success rate was 78%. Comparison with spectra of similar fungi dried on the ATR crystal showed that both types of spectra were very similar, indicating that drying the samples on the ATR crystal is not required and can be replaced by mathematical post-processing of the spectra. For routine analyses that involve rapid screening of very large amounts of samples, this approach allows for increasing significantly the number of samples that can be analyzed daily.

scholarly journals Structural changes of protein antigens due to adsorption onto and release from aluminium hydroxide using FTIR–ATR

2007 ◽  
Vol 21 (4) ◽  
pp. 211-226 ◽  
Author(s):  
Yiwu Zheng ◽  
Xuxin Lai ◽  
Henrik Ipsen ◽  
Jørgen Nedergaard Larsen ◽  
Henning Løwenstein ◽  
...  
Keyword(s):  
Immune Response ◽  
Aluminium Hydroxide ◽  
Structural Changes ◽  
Structural Integrity ◽  
Structural Information ◽  
Cd Spectroscopy ◽  
Attenuated Total Reflection ◽  
Protein Antigens ◽  
Recovery Curves ◽  
Atr Spectroscopy

Structural integrity of antigens upon adsorption and release is not only important for investigating vaccine immunogenicity, but also for the epitope specificity of the resulting immune response and hence therapeutic efficacy. Moreover, the structural information is also important for understanding the mechanism of how adjuvants can enhance the immune response. However, little is known about an antigen's structure when it is adsorbed on and subsequently released from aluminium adjuvants. In this study, the structures of two protein antigens, bovine serum albumin and β-lactoglobulin, were investigated using Fourier transform infrared–attenuated total reflection (FTIR–ATR) spectroscopy. The secondary structures of both model antigens change when adsorbed to aluminium hydroxide. The structural perturbation depends on the amount of adsorbed protein. Maximal adsorption gives a more native-like structure. This may indicate that protein is adsorbed in different manners depending on the concentration. The adsorbed antigens are released using phosphate buffer pH 7.4 (PB). The recovery is approximate 80% after 40 min in the presence of PB. The recovery curves of both proteins also indicate two different adsorption modes. FTIR–ATR and circular dichroism (CD) spectroscopy yield similar results suggesting that the adsorbed antigens refold to their native-like state after release.

FTIR/ATR Spectroscopy with Stability for Determination of HGB in Human Whole Blood

2012 ◽  
Vol 468-471 ◽  
pp. 1663-1666
Author(s):  
Tao Pan ◽  
Wen Jie Huang ◽  
Hao Yin
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Whole Blood ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Human Whole Blood ◽  
Reliable Model ◽  
Smoothing Parameters ◽  
Atr Spectroscopy

Fourier transform infrared spectroscopy (FTIR) and attenuated total reflection (ATR) combined with partial least-squares (PLS) and Savitzky-Golay (SG) smoothing were successfully applied for rapid no-reagent determination of hemoglobin (HGB) in human whole blood. The optimal SG smoothing parameters OD, DP, NSP and PLS factor were 1, 2, 49 and 14, respectively. The modeling effect M-SEPAve, M-RP,Ave, M-SEPStd, and M-RP,Std were 6.73g/L, 0.850, 0.306g/L, and 0.015, respectively. The validation effect V-SEP and V-RP were 6.83g/L and 0.864, respectively. The method provided a reliable model with stability for clinic application of FTIR/ATR.

Effects of Hydrogen Peroxide on Human Dentin Structure

2007 ◽  
Vol 86 (11) ◽  
pp. 1040-1045 ◽  
Author(s):  
T. Jiang ◽  
X. Ma ◽  
Y. Wang ◽  
Z. Zhu ◽  
H. Tong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Human Dentin ◽  
Mineral Components ◽  
Atr Spectroscopy ◽  
Demineralized Dentin ◽  
Chemical Evidence

It has been hypothesized that hydrogen peroxide (H2O2) bleaching may cause destruction of dentin by a mechanism of protein oxidation. However, to our knowledge, there has been no direct chemical evidence to validate this viewpoint. To investigate the effects of H2O2 on the structure of human dentin, we used Fourier transform infrared spectroscopy (FTIR) and attenuated total reflection (ATR) spectroscopy. Human intact dentin specimens were treated either with 30% H2O2 or Hanks’ balanced salt solution (HBSS). Significant differences were observed in ATR spectra parameters. Additionally, demineralized dentin specimens were also tested. They were completely dissolved in the H2O2, but remained intact in the 0.1 N HCl and HBSS. The results suggested that H2O2 attacked both the organic and mineral components of dentin. Destruction of the organic components was mainly because of the oxidizing ability of H2O2, while changes in the mineral components were probably due to its acidity.

scholarly journals Distinguishing active from quiescent disease in ANCA-associated vasculitis using attenuated total reflection Fourier-transform infrared spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam D. Morris ◽  
Camilo L. M. Morais ◽  
Kássio M. G. Lima ◽  
Daniel L. D. Freitas ◽  
Mark E. Brady ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Unmet Need ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Remission Induction ◽  
Disease Remission ◽  
Anca Associated Vasculitis ◽  
Active Disease ◽  
Quiescent Disease

AbstractThe current lack of a reliable biomarker of disease activity in anti-neutrophil cytoplasmic autoantibody (ANCA) associated vasculitis poses a significant clinical unmet need when determining relapsing or persisting disease. In this study, we demonstrate for the first time that attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy offers a novel and functional candidate biomarker, distinguishing active from quiescent disease with a high degree of accuracy. Paired blood and urine samples were collected within a single UK centre from patients with active disease, disease remission, disease controls and healthy controls. Three key biofluids were evaluated; plasma, serum and urine, with subsequent chemometric analysis and blind predictive model validation. Spectrochemical interrogation proved plasma to be the most conducive biofluid, with excellent separation between the two categories on PC2 direction (AUC 0.901) and 100% sensitivity (F-score 92.3%) for disease remission and 85.7% specificity (F-score 92.3%) for active disease on blind predictive modelling. This was independent of organ system involvement and current ANCA status, with similar findings observed on comparative analysis following successful remission-induction therapy (AUC > 0.9, 100% sensitivity for disease remission, F-score 75%). This promising technique is clinically translatable and warrants future larger study with longitudinal data, potentially aiding earlier intervention and individualisation of treatment.

Analysis of Captan on Nitrile Glove Surfaces Using a Portable Attenuated Total Reflection Fourier Transform Infrared Spectrometer

2005 ◽  
Vol 59 (6) ◽  
pp. 724-731 ◽  
Author(s):  
R. N. Phalen ◽  
Shane S. Que Hee
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Surface Films ◽  
Airflow Rate ◽  
Infrared Spectrometer ◽  
Ftir Spectrometer ◽  
Selection Of ◽  
Solvent Volume

This study developed a method to produce uniform captan surface films on a disposable nitrile glove for quantitation with a portable attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometer. A permeation test was performed using aqueous captan formulation. Uniform captan surface films were produced using solvent casting with 2-propanol and a 25 mm filter holder connected to a vacuum manifold to control solvent evaporation. The coefficient of variation of the reflectance at 1735 ± 5 cm−1 was minimized by selection of the optimum solvent volume, airflow rate, and evaporation time. At room temperature, the lower to upper quantifiable limits were 0.31–20.7 μg/cm2 ( r = 0.9967; p ≤ 0.05) for the outer glove surface and 0.55–17.5 μg/cm2 ( r = 0.9409; p ≤ 0.05) for the inner surface. Relative humidity and temperature did not affect the uncoated gloves at the wavelength of captan analysis. Glove screening using ATR-FTIR was necessary as a control for between-glove variation. Captan permeation, after 8 hours exposure to an aqueous concentration of 217 mg/mL of Captan 50-WP, was detected at 0.8 ± 0.3 μg/cm2 on the inner glove surface. ATR-FTIR can detect captan permeation and can determine the protectiveness of this glove in the field.

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